In this technical field, cleaning of the injection device is a very important step in using the injection device since it is used to fill containers, for example bottles, with products that are to be ingested by consumers or applied on the skin of a consumer. Therefore, since the injection device is to be used for filling successive containers or preforms, the injection device has to be cleaned regularly in order to avoid risks of contamination or of soiling the containers or preforms.
Such an injection device is for example disclosed in FR-2 523 720, wherein the filling of the chamber and the injection are controlled by flexible membranes, which are easier to clean than conventional valve systems used in injection devices.
However, the structure of the injection device remains complicated and some areas of the device, in particular around the piston and the flexible membranes, are hardly accessible for the cleaning products. Consequently, in order to fully clean the injection device, parts of the device should be removed from the device and cleaned manually.
Such a step is time consuming and requires the machine for filling containers or for forming containers to be stopped, which greatly reduces the throughput of the machine.
WO-95/11428 discloses an injection device arranged to inject a predetermined quantity of liquid through the outlet of the injection device. However, this injection device does not allow control of the pressure of the injected liquid, which is not suitable for injecting a liquid inside a container at a controllable and possibly variable pressure.
One of the aims of the invention is to overcome these drawbacks by proposing an injection device of simple structure, wherein all the parts of the device are easily accessible to cleaning products, without having to dismantle the injection device.